1. Field of the Invention
The present invention relates to a reciprocating power tool such as a reciprocating saw and more particularly, to a technique of reducing vibration in actual operation of cutting a work-piece.
2. Description of the Related Art
Japanese non-examined laid-open Patent Publication No. 2001-9632 discloses a reciprocating saw as an example of a reciprocating power tool. The known reciprocating saw includes a motion converting mechanism for causing a slider to reciprocate via the rotational movement of the motor. A tool bit is mounted on the end of the slider. Further, the motion converting mechanism has a counter weight. When the slider reciprocates, the counter weight reciprocates in a direction opposite to the reciprocating direction of the slider, or, with a 180° phase shift with respect to the slider. As a result, vibration caused by reciprocating movement of the slider can be reduced as much as possible, so that the vibration of the power tool can be reduced.
By using such a counter weight that reciprocates with a 180° phase shift with respect to the reciprocating movement of the slider, the momentum, mainly including the inertial force, can be reduced between the slider and the counter weight in the axial direction of the slider. Thus, effective vibration reduction can be realized. However, the weight of the power tool itself is increased by the weight of the counter weight because the counter weight is additionally provided as the motion converting mechanism. Therefore, further improvement is desired in this respect.